The little finger FDS slip is the most variable of the four slips — it is absent in approximately 21% of individuals, and in many others the slip is too thin for functional use. This variability must be assessed before planning any little finger FDS-based procedure.
| Origin | Medial epicondyle — humeral-ulnar head |
|---|---|
| Insertion | Base of the middle phalanx of the little finger |
| Nerve Supply | Median nerve (C7, C8, T1) |
| Blood Supply | Ulnar artery |
| Actions | Flexes the PIP joint of the little finger; Assists little MCP flexion |
|---|
Little FDS slip absence or hypoplasia (21% prevalence) must be confirmed before planning FDS-based ring finger or other reconstructions using the little slip. In clinical assessment, the little finger cannot independently flex its PIP joint in isolation as reliably as other fingers, partly due to this slip variability.
Tested by isolated little PIP flexion with adjacent fingers held extended — may be absent or very weak.
Pre-operative assessment of little FDS slip presence required before planning FDS-based reconstructions, with absence found in 21% of patients.
